Improvement in the methods of blasting



a. Fn'lssze. Methods uf Bla-sting.

Patented Feb. 10.874. I

No.l47;254.

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IMPROVEMENT IN THE METHODS OF BLASTING.

Specification forming part of Letters Patent No. 147,254, dated February 10, 1874, application filed December 4, 1873.

To all whom it may concern:

Bc it known that I, GIDEON FRISBEE, of Reading, in the county of Berks and State of Pennsylvania, have invented a new and useful Improvement in the Art of Blasting ltock; and I do hereby declare the following to be a full, clear, and exact description thereof, which will enable others skilled in the said art to practice my invention.

This improvement is particularly applicable to sinking shaftsv and excavating tunnels and consists in boring the drill-holes to a suflicient depth for the insertion and explosion of several charges, and inserting, before each charge, a plug, which, without reaching the bottom of the hole, shall form a bed or recoilblock to resist the inward pressure of the explosion.

The mode in which I prefer to practice this invention is as follows: I first bore, preferably by means of the Leschot diamond drill, a number of holes within the space to be excavated, which holes may, if the capacity of the machinery permits, be of the length or depth of the desired excavation. When the boring machinery has been withdrawn from a l1olc,I insert therein a plug, which shall constitute a recoil-block or artificial bottoni to resist the inward pressure resulting from the explosion ot' the charge inserted above it. The accompanying drawing represents a plug which I have devised for this purpose, but the form of plug there shown is not essential to this invention, it being only requisite that the plug should be of such construction, or that it should be so arranged in the hole, as to support the charge and withstand the pressure of the explosion; and this, whether, previously to its insertion, the hole be enlarged or cut in any way to support the plug better against the explosion or not, or of whatever material the plug be composed, and whether it be iixed in the hole by wed ging, rammin g, swelling, or otherwise.

Figure l of the drawing is an elevation of the plug; and Fig. 2, a section thereof, taken through its axis.

A is a metal cylinder, whose diameter` is slightly less than that of the hole, and whose lower end is wedge-shaped. O is a bolt, passing through a hole in the middle of A, and

bolt C, and

made with a screw-thread on its lower end, a lug, H, on one side of its upper end, and a collar, F, fitting into a recess in the upper part of A. B B are two pieces of metal, through which bolt C also passes, made with inclined inner surfaces at their upper ends, to receive the lower end of A. E is a recess, made in B B to receive the nut D, which is screwed on C. G is a cap screwed into A to keep the collar F in place. I is a cap, tting on top of A, and covering the upper end of made with a conical top, K, and a projecting knob, L, which assists in removingitfrom thehole. Mis a packin g-ring, oflead or other soft metal, leather, or other suitable substance, which fits over cone K, and is forced downward and outward by the explosion of the charge, so as to till the hole and prevent gas from escaping into it.

In operation, the plug, without the cap I, is inserted into the hole, at the proper depth, by means of a socket-wrench, which is placed on the upper end of the boltC and then turned,

so as to force B B upward by the action of the screw and nut, thereby forcing B B apart and against the walls of the hole,'and wedging the plug firmly therein. The wrench'is then removed, and cap I and packing-rin g M put on.

rIhe plug having been thus fixed in position, the charge is then inserted, tam'ped, and fired in the usual manner. The charges'in all the holes should 'be iired simultaneously. The force of the explosion is received on the packing-ring M, cap I, and cylinder A, we( ging the latter in farther between B B, and thereby forcing the plug more rmly against the sides of the hole.

After ring, the plug may be removed or inserted deeper int-o the hole, by iirst withdrawing the cap I and packing-rin g by means of a suitable hook applied to knob L, and then loosening the plug by means of the socketwrench, which is now turned in the reverse direction. This wrench should have a lateral recess on each side of the groove, which receives the lug II, so as to raise and lower the plug in vertical holes.

rIhe plugs having been again fixed in the holes at the proper distance to support the charges, as above described, the charging, tamping, and firing are again repeated, and

the operation continued as long as may be necessary.

Vhat I claim as my invention, and desire to secure by Letters Patent of the United States, is-

The method, substantially as above described, of blasting rock by boring` a hole to a depth sufcient for the insertion and explosion of several charges, and inserting, before each charge, a plug, which forms a bed to support the charge and withstand the explosion, but which does not reach the bottom of the hole.

GlDEON FRISBEE.

Witnesses A Y DANIEL C. WIELAND F. M. BANKS. 

